Space-borne detectors have been used to search for evidence of the products of of dark matter annihilation, particularly \(\gamma \) -rays and cosmic-ray positrons.
These searches have conservatively produced constraints on dark matter annihilation, both from cosmic \(\gamma \) -ray studies [1]} and cosmic-ray positron studies [2]}. However, analyses of the Fermi-LAT data have indicated the existence of an "excess" flux of \(\gamma \) -rays above that expected from cosmic rays interacting with interstellar gas. This flux appears to be extended around the region of the galactic center. It appears to peak in the 2 – 3 GeV energy range. This excess has been interpreted to be a possible indication of the annihilation of weakly interacting dark matter (WIMP) particles having a mass in the 20 – 45 GeV range, annihilating primarily into quarks or, less likely, in the 7 – 12 GeV mass range annihilating primarily into charged \(\tau \)  leptons [3]}, [4]}. Models involving other annihilation channels have also been considered [5]}. We note, however, the determination of various possible components of \(\gamma \) -ray emission from the galactic center is complicated and the \(\gamma \) -ray data are not precise enough to point to a unique origin. Other possible interpretations of this excess that include other contributions to the \(\gamma \) -ray flux in the region of the galactic center have been suggested [6]}.
